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This invention relates to a method and apparatus for applying blown insulation.
A common method of applying insulation into cavities, such as attic spaces and the like, is to blow the insulation into place. This type of insulation is generally known as blown or loose fill insulation. Typical loose fill insulation materials are usually fibrous materials, such as fiberglass, cellulose, rockwool, or the like.
To apply loose fill insulation, the insulation material is loaded into a hopper. The material is mechanically agitated, and by means of air pressure is blown through a flexible hose manufactured of plastic, such as a urethane, polyethylene, vinyl, or the like. The hose is usually between 2 and 4 inches in diameter and frequently 100 feet or longer in length. The installer, by manipulating the direction of the end of the hose, lofts the insulation into the proper areas to the desired depth and density for the purpose of sound and thermal insulation. This insulation is quite effective, particularly in flat spaces, and has superior insulation properties because there are no voids or gaps, as frequently found with rolled insulation materials.
Although loose-fill insulation has superior insulation properties, it has several problems, mostly associated with the installation of the insulation. The insulation, after it is blown, tends to settle and decrease in thickness over time. It is known that the blown insulation, particularly for cellulosic materials, forms an unstable matrix that settles into a stable and more dense matrix over time. Therefore, a major problem is that the operator must compensate for the settling, a calculation that is made difficult by the uncertainty of determining how much any given applied layer of insulation will settle, and how long it will take to settle to its equilibrium. An insulation installer must install the proper thickness calculated as settled inches, as most manufactures only rate the insulation value at settled inches and not installed inches. If the installer underestimates the settling, the thickness, of the insulation will eventually settle to a depth below specification and the insulating value of the insulation will be inadequate for that specified. Settling can be as much as 15 to 20%, and therefore is a significant problem. The large extent, the uncertainty and the variability of the settling process has mitigated against any standard for as-installed blown insulation, and it is a continuing dilemma for insulation installers who wish to guarantee a settled insulation thickness.
In response to this problem, methods have been proposed to accelerate or eliminate settling. In U.S. Pat. No. 4,773,960 to Vincelli et al. it is proposed to coat the insulation material with a dry deactivated adhesive. Water is injected into the hose as the material is blown through it, which moistens the fiber particles and activates the adhesive. The applied insulation then sets, which reduces settling with time. The problem with this method is that it involves treating the insulation material with a dry-adhesive additive that adds cost to the material and may increase its density. After installation, there is still an initial settling of up to about 10%. In addition, in a humid environment, the adhesive material may activate during storage. Further, the use of water complicates the installation apparatus and introduces more possibilities of equipment corrosion. In certain climates the water lines and pumps are subject to damage by freezing. It is also frequent that a construction site have no water, which requires the construction crews to bring their own water.
There are other problems associated with blown insulation. With conventional dry blown systems the fibers disperse wildly as they exit the hose, which can cause extreme dust problems, even to the degree that the installer may be unable to see the insulation as he is applying it, which complicates his ability to lay a layer of the proper depth. This combined with the settling problem results in an uneven layer of insulation with inadequate R-rating. In addition, the dispersed fibers tend to be attracted and adhere to wooden structural members, where they cannot function as insulation.
Yet, another problem is that when the dry loose-fill insulation is blown through a plastic hose, the hose becomes statically charged as the particles of insulation are blown through the hose. The static charges in the hose subject the operator to frequent and strong static shocks whenever he contacts any grounded surface, such as plumbing, or an air duct, etc.
It is, therefore, an object of the invention to provide an apparatus and method of installing blown insulation that decreases settling of as-blown insulation material.
Another object of the invention is to provide an as-blown insulation material in a stable matrix with minimal settling after installation.
Another object of the invention is an apparatus and method for increasing the control of the application of blown insulation by, decreasing air-born dust and improving visibility.
Another object of the invention is an apparatus and method for applying blown insulation that minimized the amount of insulation material that uselessly sticks to framing members and surrounding wooden structures.
Another object of the invention is to provide an apparatus and method for applying blown insulation in which static shocks to the operator are eliminated.
Another object of the invention is to provide an apparatus and method for applying blown insulation in which the static charges in the insulation fibers and the application hose are dissipated.
Further objects of the invention will become evident in the description below.
It has been unexpectedly found in development of the present invention to eliminate shock to the operator that a major factor contributing to settling is the static charge created when the insulation material is blown through a plastic hose. It is believed that since each fiber has the same charge, they repel each other and form an unstable matrix when initially blown. Eventually, the static charges dissipate allowing the fibers to settle into a more stable and more dense settled matrix. Since the dissipation of the static charge is determined by numerous uncontrollable and variable factors, the rate and extent of settling of such blown insulation material has remained unpredictable. It has been found that the static charge in conventionally blown cellulosic insulation can lead to more than 40% of the total settling.
Accordingly, in the practice of the invention, preventing the build-up of static charge in the fibers as they leave the hose has substantially reduced the settling problem. It has been found that by blowing the insulation material through a grounded electrically conductive hose to dissipate any static charge, the total settling of the as-blown insulation is reduced by up to 40%, or more. The as-blown insulation material forms a more stable, static-free matrix, without the addition of water and adhesives.
It has also been found that practice of the invention will substantially reduce the air-borne dust problem. It has been found that a significant factor in the dispersion of dust is the static build-up in the fiber particles. Elimination of the static charge in the hose dissipates static charges in the particles and substantially reduces air-born dust. In addition, the tendency of the fiber to adhere to wooden structural members is also significantly reduced. With the reduction of dust and the fiber adhering to structural members, the installer can easily monitor the depth of the applied fiber. Accordingly, the applied fiber is applied more evenly, and the insulated area is much cleaner.
An unexpected benefit from practice of the present invention, is that friction of the fiber passing through the hose is significantly reduced. This allows for a faster application rate for a given hose diameter and hose length. This not only decreases the application time, but reduces the work load on the blowers, leading to power savings and cooler operating temperatures for the blower.
In summary, the dissipation of static charges in the blowing hose to reduce static shock to the operator also achieves unexpected and surprising advantages. The settling of the applied insulation is significantly reduced, air-born dust is minimized, insulation adhering to the structural members is significantly decreased, and the rate of application is increased. Application of the insulation is more predictable and even. This is due to the reduction of settling, the better visibility of the operator, and the reduction the insulation adhering to structural members. The level of comfort of the operator is materially increased by the reduction in dust level and the absence of static shocks when he touches a ground. Operator efficiency is increased because he can with greater ease apply an even insulation layer at a faster application rate. The invention is of particular advantage for cellulosic insulation materials, since the settling problem is more pronounced for these materials. Settling in conventionally blown fiber-glass insulation materials is less than for cellulosic, so the unexpected advantage of reduced settling is less pronounced. The other advantages would still be unexpected, i.e., eliminating shock to the operator, the advantages of reduced dust, faster application rate, reduced scattering and less attraction to framing.
In summary, the present invention is an apparatus for blowing insulation material into the space to be insulated which comprises;
blower for creating a stream of air,
shopper and feeder structure for mechanically agitating and controllably introducing insulation material into the stream of air,
a flexible hose attached to the feed structure/blower assembly at a proximate end through which the stream of air with entrained insulating material is directed and exits through a distal outlet end of the hose, the hose comprising a grounded conductor disposed at or near the outlet end to dissipate electrical charge and provide an essentially charge-free stream of entrained insulation material leaving the outlet distal end.
Another aspect of the invention is a method for blowing insulation material into a space to form a dry, static-free matrix of blown insulation material which comprises;
entraining the insulation in a stream of air and directing the entrained insulation through a flexible hose having a proximate inlet end and a distal outlet end,
dissipating static charges by providing an grounded electrical conductor at or near the outlet end sufficient to provide a static free stream of entrained insulation material exiting the outlet end,
directing the outlet end to direct the static free stream of insulation material into the space to be insulated.